Structure of the Earth

The Earth is made up of 3 main layers:______________

______________

______________

The CrustThis is where we live!

The Earth’s crust is made of:

_________________

- thick (10-70km)- buoyant (_____ _______ than oceanic crust) - mostly old

__________________

- thin (~7 km)- dense (_______ under continental crust)- young

What is Plate Tectonics?

• If you look at a map of the world, you may notice that some of the continents could fit together like pieces of a puzzle.

Plate Tectonics• The Earth’s crust is divided into ___ major plates

which are moved in various directions.

• This plate motion causes them to __________, ______ _______, or __________ against each other.

• Each type of interaction causes a characteristic set of Earth structures or “tectonic” features.

• The word, tectonic, refers to the ___________ of the crust as a consequence of plate interaction.

World Plates

What are tectonic plates made of?

• Plates are made of rigid ____________.

The lithosphere is made up of the _________and the upper part of the __________.

What lies beneath the tectonic plates?

• Below the lithosphere (which makes up the tectonic plates) is the ____________.

Plate Movement• “Plates” of lithosphere are moved around by the

underlying hot mantle ___________ cells.

Source: Your Planet Earth

The Action Is At The Plate Boundaries!

• ____________

• ____________

• ____________

Three types of plate boundaries

Source: Your Planet Earth

• Spreading ridges_______________________________________

_______________________________________

Divergent Boundaries

Source: Your Planet Earth

Age of Oceanic Crust

Courtesy of www.ngdc.noaa.gov

• Iceland has a ___________ plate boundary running through its middle

Iceland: An example of _______________ __________

Source: Your Planet Earth

• There are three styles of convergent plate boundaries__________________________________

__________________________________

__________________________________

Convergent Boundaries

• Forms mountains, e.g. ________________ and _____________________

Continent-Continent Collision

Himalayas

• Called __________________

Continent-Oceanic Crust Collision

Source: Your Planet Earth

• _________ ___________ subducts underneath the continental lithosphere

• Oceanic lithosphere heats and dehydrates as it subsides

• The melt rises forming ___________

• E.g. _____ _________

Subduction

Source: Your Planet Earth

• When two oceanic plates collide, one runs over the other which causes it to _________ into the mantle forming a _____________ _________.

• The subducting plate is bent downward to form a _____ ________ depression in the ocean floor called a __________.

• The worlds deepest parts of the ocean are found along trenches. E.g. The Mariana Trench is _____ ________!

Ocean-Ocean Plate Collision

• Where plates _______ ______ each other

Transform Boundaries

Above: View of the San Andreas transform fault

Source: Your Planet Earth